Poliomyelitis is an ancient disease and has been
one of the most dreaded since pre-biblical times. 4000 year-old Egyptian
carvings show a typical polio withered leg.

Before the 1900's, polio was endemic and most
polio occurred in infants, hence the name "infantile paralysis".
Few developed paralysis and poor hygiene meant that most people were exposed
to the virus early in life, thus building active immunity. In fact,
everyone had polio, just as we all had measles, mumps and chicken pox.

Polio is a gastro virus ie "a tummy wog". 95%
of people were not even aware that they had had polio, having no symptoms
or just a 'flu-like illness. The other 5% had either weakness or
some paralysis. Only 2.5% were left with any visible effects from
polio. The mortality rate is 3% of known polio cases ie 15 in 10,000
pop.

EPIDEMICSThe first recorded "epidemics" were around 1916.
Fear swept communities. Hospitals ran out of room. In NZ, patients
were nursed in tents in the hospital grounds. Probably in other parts
of the world too. Sporadic isolated cases were the norm until 1937-38
when again there was a major outbreak. In post-World War 2 years,
epidemics escalated until the Salk vaccine was available in 1956.
By the 1950's equal numbers of adults as children were contracting polio.
Polio had become a disease of cleanliness. It affected the more affluent
people and at an older age was more severe in its paralysis.

VIRUSPolio is a picornavirus (pico = small; rna =
RNA, part of cell nucleus). Rhinovirus belongs to the same family
and causes colds. It replicates best at temperatures of 33O as found
in the nose. Enteroviruses, which include Hepatitis A, echovirus,
coxsackie and polio, replicate better at 37O - body temperature.
Enteroviruses are resistant to gastric acidity and bile. There are
3 strains of polio. Most epidemics are caused by Type 1. Some
people have had polio twice, having the misfortune to catch different strains
in different epidemics.

COURSE OF DISEASEPolio enters through the mouth and divides in
the lymphoid tissue of the pharynx or intestine. If the body cannot
stop the virus at this stage, it enters the bloodstream and may cause flu'-like
symptoms. If the disease is able to progress further, (ie with poor
immune function), the virus enters the anterior horn cells of the spinal
column resulting in weakness and paralysis, which is then recognised as
polio.

The polio virus uses the RNA of the host cell
to enable it to divide. It continues to divide until it explodes
the host cell destroying it. Roughly 1,000 new poliovirus can be
released from one host cell to seek their own host cell and repeat the
process. Each cycle takes about 10 hours. Polio may continue to replicate
in the gut and faeces may still be infectious for months after all symptoms
have gone.

Polio can affect any and many parts of the body.
Some people have an arm or a leg weakened or paralysed. There may
be any combination, opposite arms and legs, the same side, both legs, face,
eye, hearing, swallowing only, voice, breathing, scoliosis (curvature of
spine) etc. If bulbar polio occurred, involving swallowing or breathing,
patients may need tube feeding or an iron lung. Death was possible.

The extent of damage depends on how many cells
are destroyed completely and where they are. Most polio survivors
have scattered unapparent damage in many parts of the body that can only
be determined by EMG testing. If there is extensive destruction
in an area, permanent paralysis will result. Some nerve cells may
survive in a weakened state and improve over time. Other surviving
nerves may send out sprouts to re-activate muscles that have lost their
nerves supply, resulting in further recovery years later.A few people were left requiring help breathing.
Some are still using iron lungs. Many had calipers initially but
over time were able to walk without them. Some were left using calipers,
crutches, sticks or wheelchairs. Most people recovered to lead normal
lives - many with no visible effects from polio, others with a variety
of limps. Some had surgery to improve muscle and joint function.
There was pride that their efforts to recover were rewarded. Polio
was gone.However, around 1980 it was realised that polio had another round
to go. Although polio people from previous eras had had some deterioration
later in life,it wasn't until the huge numbers of polio survivors
from the post war years began having problems and talking about this, that
it was realised there are "Late Effects" of polio that needed to be investigated
further.

Symptoms that are occurring can be generalised
and non-specific. They may include some or all.

Diagnosis is one of exclusion. There is
no definite test available for the late effects of polio.

DEFINITIONSThe Late Effects of Polio (LEP) is a general
term covering new health problems resulting from polio-caused impairment
including arthritis, tendinitis, bursitis and other repetitive motion problems.

Post Polio Syndrome (PPS) is a sub-category
that includes a symptom cluster of new weakness, fatigue and pain, resulting
in declining ability and/or new disability.

Post Polio Progressive Muscular Atrophy (PPMA)
is
a sub-group of PPS defined as progressive new weakness and atrophy in muscles
and this can be demonstrated on EMG.

AN INTERNATIONAL CAUTION -The following drugs may worsen the symptoms of
polio survivors and should be avoided or used with caution: Alert
your doctor to these.

Treatment has mainly been to advise people to
reduce activity levels, building frequent rest periods into the day.
Exercise to maintain and improve muscle function advises exercising at
20% of your capacity only, to reduce further deterioration. Local
research by polio people in WA has improved on this advice, enabling many
in WA to return to previous activities again without the pain and fatigue
encountered previously. We can continue to be independent and in
control of our lives.